1 /*
2 * Copyright (c) 2013, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24
25 package org.graalvm.compiler.phases.common;
26
27 import org.graalvm.compiler.core.common.type.FloatStamp;
28 import org.graalvm.compiler.core.common.type.Stamp;
29 import org.graalvm.compiler.debug.DebugCloseable;
30 import org.graalvm.compiler.debug.GraalError;
31 import org.graalvm.compiler.graph.Graph;
32 import org.graalvm.compiler.graph.Node;
33 import org.graalvm.compiler.nodes.AbstractBeginNode;
34 import org.graalvm.compiler.nodes.AbstractMergeNode;
35 import org.graalvm.compiler.nodes.BeginNode;
36 import org.graalvm.compiler.nodes.ConstantNode;
37 import org.graalvm.compiler.nodes.EndNode;
38 import org.graalvm.compiler.nodes.IfNode;
39 import org.graalvm.compiler.nodes.LogicNode;
40 import org.graalvm.compiler.nodes.MergeNode;
41 import org.graalvm.compiler.nodes.NodeView;
42 import org.graalvm.compiler.nodes.ShortCircuitOrNode;
43 import org.graalvm.compiler.nodes.StructuredGraph;
44 import org.graalvm.compiler.nodes.ValueNode;
45 import org.graalvm.compiler.nodes.calc.ConditionalNode;
46 import org.graalvm.compiler.nodes.calc.FloatEqualsNode;
47 import org.graalvm.compiler.nodes.calc.FloatLessThanNode;
48 import org.graalvm.compiler.nodes.calc.IntegerEqualsNode;
49 import org.graalvm.compiler.nodes.calc.IntegerLessThanNode;
50 import org.graalvm.compiler.nodes.calc.NormalizeCompareNode;
51 import org.graalvm.compiler.phases.Phase;
52
53 public class ExpandLogicPhase extends Phase {
54 private static final double EPSILON = 1E-6;
55
56 @Override
57 @SuppressWarnings("try")
58 protected void run(StructuredGraph graph) {
59 for (ShortCircuitOrNode logic : graph.getNodes(ShortCircuitOrNode.TYPE)) {
60 processBinary(logic);
61 }
62 assert graph.getNodes(ShortCircuitOrNode.TYPE).isEmpty();
63
64 for (NormalizeCompareNode logic : graph.getNodes(NormalizeCompareNode.TYPE)) {
65 try (DebugCloseable context = logic.withNodeSourcePosition()) {
66 processNormalizeCompareNode(logic);
67 }
68 }
69 graph.setAfterExpandLogic();
70 }
71
72 private static void processNormalizeCompareNode(NormalizeCompareNode normalize) {
73 LogicNode equalComp;
74 LogicNode lessComp;
75 StructuredGraph graph = normalize.graph();
76 ValueNode x = normalize.getX();
77 ValueNode y = normalize.getY();
78 if (x.stamp(NodeView.DEFAULT) instanceof FloatStamp) {
79 equalComp = graph.addOrUniqueWithInputs(FloatEqualsNode.create(x, y, NodeView.DEFAULT));
80 lessComp = graph.addOrUniqueWithInputs(FloatLessThanNode.create(x, y, normalize.isUnorderedLess(), NodeView.DEFAULT));
81 } else {
82 equalComp = graph.addOrUniqueWithInputs(IntegerEqualsNode.create(x, y, NodeView.DEFAULT));
83 lessComp = graph.addOrUniqueWithInputs(IntegerLessThanNode.create(x, y, NodeView.DEFAULT));
84 }
85
86 Stamp stamp = normalize.stamp(NodeView.DEFAULT);
87 ConditionalNode equalValue = graph.unique(
88 new ConditionalNode(equalComp, ConstantNode.forIntegerStamp(stamp, 0, graph), ConstantNode.forIntegerStamp(stamp, 1, graph)));
89 ConditionalNode value = graph.unique(new ConditionalNode(lessComp, ConstantNode.forIntegerStamp(stamp, -1, graph), equalValue));
90 normalize.replaceAtUsagesAndDelete(value);
91 }
92
93 @SuppressWarnings("try")
94 private static void processBinary(ShortCircuitOrNode binary) {
95 while (binary.usages().isNotEmpty()) {
96 Node usage = binary.usages().first();
97 try (DebugCloseable nsp = usage.withNodeSourcePosition()) {
98 if (usage instanceof ShortCircuitOrNode) {
99 processBinary((ShortCircuitOrNode) usage);
100 } else if (usage instanceof IfNode) {
101 processIf(binary.getX(), binary.isXNegated(), binary.getY(), binary.isYNegated(), (IfNode) usage, binary.getShortCircuitProbability());
102 } else if (usage instanceof ConditionalNode) {
103 processConditional(binary.getX(), binary.isXNegated(), binary.getY(), binary.isYNegated(), (ConditionalNode) usage);
104 } else {
105 throw GraalError.shouldNotReachHere();
106 }
107 }
108 }
109 binary.safeDelete();
110 }
111
112 private static void processIf(LogicNode x, boolean xNegated, LogicNode y, boolean yNegated, IfNode ifNode, double shortCircuitProbability) {
113 /*
114 * this method splits an IfNode, which has a ShortCircuitOrNode as its condition, into two
115 * separate IfNodes: if(X) and if(Y)
116 *
117 * for computing the probabilities P(X) and P(Y), we use two different approaches. The first
118 * one assumes that the shortCircuitProbability and the probability on the IfNode were
119 * created with each other in mind. If this assumption does not hold, we fall back to
120 * another mechanism for computing the probabilities.
121 */
122 AbstractBeginNode trueTarget = ifNode.trueSuccessor();
123 AbstractBeginNode falseTarget = ifNode.falseSuccessor();
124
125 // 1st approach
126 // assumption: P(originalIf.trueSuccessor) == P(X) + ((1 - P(X)) * P(Y))
127 double firstIfTrueProbability = shortCircuitProbability;
128 double secondIfTrueProbability = sanitizeProbability((ifNode.getTrueSuccessorProbability() - shortCircuitProbability) / (1 - shortCircuitProbability));
129 double expectedOriginalIfTrueProbability = firstIfTrueProbability + (1 - firstIfTrueProbability) * secondIfTrueProbability;
130
131 if (!doubleEquals(ifNode.getTrueSuccessorProbability(), expectedOriginalIfTrueProbability)) {
132 /*
133 * 2nd approach
134 *
135 * the assumption above did not hold, so we either used an artificial probability as
136 * shortCircuitProbability or the ShortCircuitOrNode was moved to some other IfNode.
137 *
138 * so, we distribute the if's trueSuccessorProbability between the newly generated if
139 * nodes according to the shortCircuitProbability. the following invariant is always
140 * true in this case: P(originalIf.trueSuccessor) == P(X) + ((1 - P(X)) * P(Y))
141 */
142 firstIfTrueProbability = ifNode.getTrueSuccessorProbability() * shortCircuitProbability;
143 secondIfTrueProbability = sanitizeProbability(1 - (ifNode.probability(falseTarget) / (1 - firstIfTrueProbability)));
144 }
145
146 ifNode.clearSuccessors();
147 Graph graph = ifNode.graph();
148 AbstractMergeNode trueTargetMerge = graph.add(new MergeNode());
149 trueTargetMerge.setNext(trueTarget);
150 EndNode firstTrueEnd = graph.add(new EndNode());
151 EndNode secondTrueEnd = graph.add(new EndNode());
152 trueTargetMerge.addForwardEnd(firstTrueEnd);
153 trueTargetMerge.addForwardEnd(secondTrueEnd);
154 AbstractBeginNode firstTrueTarget = BeginNode.begin(firstTrueEnd);
155 firstTrueTarget.setNodeSourcePosition(trueTarget.getNodeSourcePosition());
156 AbstractBeginNode secondTrueTarget = BeginNode.begin(secondTrueEnd);
157 secondTrueTarget.setNodeSourcePosition(trueTarget.getNodeSourcePosition());
158 if (yNegated) {
159 secondIfTrueProbability = 1.0 - secondIfTrueProbability;
160 }
161 if (xNegated) {
162 firstIfTrueProbability = 1.0 - firstIfTrueProbability;
163 }
164 IfNode secondIf = new IfNode(y, yNegated ? falseTarget : secondTrueTarget, yNegated ? secondTrueTarget : falseTarget, secondIfTrueProbability);
165 secondIf.setNodeSourcePosition(ifNode.getNodeSourcePosition());
166 AbstractBeginNode secondIfBegin = BeginNode.begin(graph.add(secondIf));
167 secondIfBegin.setNodeSourcePosition(falseTarget.getNodeSourcePosition());
168 IfNode firstIf = graph.add(new IfNode(x, xNegated ? secondIfBegin : firstTrueTarget, xNegated ? firstTrueTarget : secondIfBegin, firstIfTrueProbability));
169 firstIf.setNodeSourcePosition(ifNode.getNodeSourcePosition());
170 ifNode.replaceAtPredecessor(firstIf);
171 ifNode.safeDelete();
172 }
173
174 private static boolean doubleEquals(double a, double b) {
175 assert !Double.isNaN(a) && !Double.isNaN(b) && !Double.isInfinite(a) && !Double.isInfinite(b);
176 return a - EPSILON < b && a + EPSILON > b;
177 }
178
179 private static double sanitizeProbability(double value) {
180 double newValue = Math.min(1.0, Math.max(0.0, value));
181 if (Double.isNaN(newValue)) {
182 newValue = 0.5;
183 }
184 return newValue;
185 }
186
187 @SuppressWarnings("try")
188 private static void processConditional(LogicNode x, boolean xNegated, LogicNode y, boolean yNegated, ConditionalNode conditional) {
189 try (DebugCloseable context = conditional.withNodeSourcePosition()) {
190 ValueNode trueTarget = conditional.trueValue();
191 ValueNode falseTarget = conditional.falseValue();
192 Graph graph = conditional.graph();
193 ConditionalNode secondConditional = graph.unique(new ConditionalNode(y, yNegated ? falseTarget : trueTarget, yNegated ? trueTarget : falseTarget));
194 ConditionalNode firstConditional = graph.unique(new ConditionalNode(x, xNegated ? secondConditional : trueTarget, xNegated ? trueTarget : secondConditional));
195 conditional.replaceAndDelete(firstConditional);
196 }
197 }
198
199 @Override
200 public boolean checkContract() {
201 return false;
202 }
203 }